Treatment with potassium bicarbonate lowers calcium excretion and bone resorption in older men and women.
BACKGROUND
Bicarbonate has been implicated in bone health in older subjects on acid-producing diets in short-term studies.


OBJECTIVE
The objective of this study was to determine the effects of potassium bicarbonate and its components on changes in bone resorption and calcium excretion over 3 months in older men and women.


METHODS
In this double-blind, controlled trial, 171 men and women age 50 and older were randomized to receive placebo or 67.5 mmol/d of potassium bicarbonate, sodium bicarbonate, or potassium chloride for 3 months. All subjects received calcium (600 mg of calcium as triphosphate) and 525 IU of vitamin D(3) daily.


METHODS
Twenty-four-hour urinary N-telopeptide and calcium were measured at entry and after 3 months. Changes in these measures were compared across treatment groups in the 162 participants included in the analyses.


RESULTS
Bicarbonate affected the study outcomes, whereas potassium did not; the two bicarbonate groups and the two no bicarbonate groups were therefore combined. Subjects taking bicarbonate had significant reductions in urinary N-telopeptide and calcium excretion, when compared with subjects taking no bicarbonate (both before and after adjustment for baseline laboratory value, sex, and changes in urinary sodium and potassium; P = 0.001 for both, adjusted). Potassium supplementation did not significantly affect N-telopeptide or calcium excretion.


CONCLUSIONS
Bicarbonate, but not potassium, had a favorable effect on bone resorption and calcium excretion. This suggests that increasing the alkali content of the diet may attenuate bone loss in healthy older adults.
Dawson-Hughes
Bess
B
Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts 02111, USA. Bess.Dawson-Hughes@Tufts.edu
Harris
Susan S
SS
Palermo
Nancy J
NJ
Castaneda-Sceppa
Carmen
C
Rasmussen
Helen M
HM
Dallal
Gerard E
GE
D000368:Aged; D001639:Bicarbonates / Q000008:administration & dosage*; D001862:Bone Resorption / Q000517:prevention & control*; D002118:Calcium / Q000652:urine*; D024042:Collagen Type I / Q000652:urine; D003404:Creatinine / Q000652:urine; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000652:urine; D011188:Potassium / Q000097:blood; D017680:Potassium Compounds / Q000008:administration & dosage*
D001639:Bicarbonates; D024042:Collagen Type I; D010455:Peptides; D017680:Potassium Compounds; C052929:collagen type I trimeric cross-linked peptide; D003404:Creatinine; C026329:potassium bicarbonate; D011188:Potassium; D002118:Calcium